Energy Converter
Convert between all major energy units: joules, kilojoules, kilowatt-hours, calories, kilocalories, BTU, electronvolts, and ergs. Type in any field to convert instantly.
Energy Unit Converter
Quick Reference: 1 kWh in other units
| Unit | Value | Context |
|---|
Frequently Asked Questions
1 kWh = 3,600,000 J (3.6 MJ). This comes from: 1 kW = 1000 J/s; 1 hour = 3600 s; so 1 kWh = 1000 × 3600 = 3,600,000 J. Electricity bills use kWh because joules would produce unwieldy large numbers for household consumption.
1 kcal = 1000 cal. Food labels list "Calories" (capital C) which are kilocalories. A "200 Calorie" snack = 200 kcal = 836,800 J. The small calorie (cal) is defined as the energy to heat 1 g of water by 1°C = 4.184 J.
1 BTU = 0.000293071 kWh; 1 kWh = 3,412.14 BTU. Common in US HVAC: a 12,000 BTU/h AC unit consumes roughly 3.5 kW of electricity. Natural gas appliances in the US are rated in BTU/h.
1 eV = 1.60218 × 10⁻¹⁹ J — the energy gained by one electron moving through a 1V potential. Used in atomic and particle physics: visible photons carry ~1.8–3.1 eV; X-rays 100 eV–100 keV; LHC protons ~6.5 TeV.
Energy Unit Conversion Factors
All conversions use joule (J) as the base unit. Every unit's value in joules:
- 1 J = 1 J (base)
- 1 kJ = 1,000 J
- 1 kWh = 3,600,000 J
- 1 cal (thermochemical) = 4.184 J
- 1 kcal = 4,184 J
- 1 BTU = 1,055.06 J
- 1 eV = 1.60218 × 10⁻¹⁹ J
- 1 erg = 10⁻⁷ J
- 1 MJ = 1,000,000 J
- 1 ft·lbf = 1.35582 J